Time Restricted Feeding in Male Runners
- Conditions
- Intermittent FastingResting Energy ExpenditureFastingAthletic PerformanceCardiovascular Risk Factor
- Interventions
- Behavioral: Time Restrictive FeedingBehavioral: Traditional Eating Pattern
- Registration Number
- NCT03569852
- Lead Sponsor
- USDA, Western Human Nutrition Research Center
- Brief Summary
This is a cross-over intervention study designed to evaluate how four weeks of time restricted feeding (16 hours fasting and 8 hours feeding), compared to four weeks of a more traditional eating pattern (12 hours fasting and 12 hours feeding), affects resting energy expenditure, subjective and biochemical markers of satiety and hunger, body composition, cardiovascular health, substrate utilization and fitness in male competitive runners.
- Detailed Description
Weight loss and improvements in body composition (increasing muscle mass and decreasing fat mass) are common goals for both dieters and athletes. Although a traditional method of achieving this has been accomplished through caloric restriction, an alternate method that is becoming increasingly popular is fasting. Fasting is described as the absence of food and/or calorie-containing beverage consumption for a period of time. The majority of people fast for 8-10 hours daily, which occurs during the overnight period when people are asleep Intermittent fasting, specifically time-restricted feeding (TRF), has recently gained popularity because it is a more sustainable means of practicing fasting and it has been shown to enhance the loss of fat mass with or without caloric restriction. It has also been shown to enhance overall health due to reports of reduced fasting glucose, insulin resistance, triglycerides, and reduced total and low-density lipoprotein (LDL) cholesterol levels in obese women. Despite its growing popularity among athletes, there is scarce research on how adhering to this type of diet pattern affects athletic performance and other biochemical markers related to health. The participants in this study will be randomly assigned to either a traditional (12/12) or a time restrictive (16/8) eating pattern in a crossover design. Each pattern will last for four weeks with a minimum two week washout in between, and the participants will consume the same calorie and macronutrient amounts based on recommendations made by the American College of Sports Medicine (ACSM) for both eating patterns. The 12/12 pattern will require subjects to consume 5 meals (breakfast, lunch, dinner, and two snacks) per day within a 12 hour period suggested to be around 8am, 10am, 12pm, 3pm, and 7pm. The 16/8 pattern will require subjects to consume 3 meals in an 8-hour period suggested to be around 12pm, 3pm, and 7pm. Subjects may only consume water, unsweetened coffee, or unsweetened tea (no artificial sweeteners) during their periods of fasting. Subjects will perform all exercise in the morning before 8 am in the fasted state. Subjects will visit the Western Human Nutrition Research Center (WHNRC) for test days at baseline (study day 1), after four weeks of the first dietary intervention (study day 28), and at the start (study day 43) and end of the second dietary intervention (study day 70), for a total of 4 test days over the duration of 10 weeks.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- Male
- Target Recruitment
- 21
- Competitive runners who have been actively training for 3 or more years
- Weigh a minimum of 110 lbs
- Training 4-6 times per week and run a minimum of 20 miles per week
- Competed in a race within past 12 months at a distance of 5 - 26.1 km
- Willing to repeat same monthly training protocol during two 4-week interventions
- VO2max range of 40-70 ml/kg/min
- Smoker
- Take medications that have cardiovascular or metabolic effects
- Taking dietary supplements
- Following a restrictive diet including restricting calories or carbohydrates
- Evidence of an eating disorder
- Major injuries in past 3 months
- Chronic disease that affects bone health, metabolism or the cardiorespiratory system
- Present with any contra-indication to exercise testing (cardiovascular abnormalities) as evaluated by study physician
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Experimental Group 1 Traditional Eating Pattern Order of treatment, time restrictive feeding (16 hours fasting and 8 hours eating) followed by traditional eating pattern (12 hours fasted and 12 hours eating). Experimental Group 2 Time Restrictive Feeding Order of treatment, traditional eating pattern (12 hours fasted and 12 hours eating) followed by time restrictive feeding (16 hours fasting and 8 hours eating). Experimental Group 1 Time Restrictive Feeding Order of treatment, time restrictive feeding (16 hours fasting and 8 hours eating) followed by traditional eating pattern (12 hours fasted and 12 hours eating). Experimental Group 2 Traditional Eating Pattern Order of treatment, traditional eating pattern (12 hours fasted and 12 hours eating) followed by time restrictive feeding (16 hours fasting and 8 hours eating).
- Primary Outcome Measures
Name Time Method Change in resting energy expenditure Study day 1, 28, 43 and 70 Resting energy expenditure will be measured using a metabolic cart
- Secondary Outcome Measures
Name Time Method Change in glucose Study day 1, 28, 43 and 70 Fasting serum will be analyzed for glucose (mmol/L) by Piccolo analyzer
Change in substrate utilization during exercise Study day 1, 28, 43 and 70 Carbohydrate and fat utilized for energy will be measured using a metabolic cart
Change in cardiovascular fitness Study day 1, 28, 43 and 70 Time to run a 10 kilometer time trial on a treadmill expressed in minutes
Change in insulin Study day 1, 28, 43 and 70 Fasting plasma will be analyzed for insulin (pmol/L) as measured by enzyme-linked immunoabsorbant assay
Change in HDL cholesterol, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for HDL cholesterol (mmol/L) by Piccolo analyzer
Change in triglycerides, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for triglycerides (mmol/L) by Piccolo analyzer
Change in body composition Study day 1, 28, 43 and 70 Body composition, including fat mass and lean body mass, will be measured by dual-energy x-ray absorptiometry (DEXA) and expressed in kilograms (kg).
Change in perceived feelings of hunger and fullness Study day 1, 28, 43 and 70 Perceived hunger and fullness will be measured using a visual analog scale. Responses will be a mark on an unsegmented line from 0 or "not at all" to 5 or "extremely."
Change in glucagon, a biomarker of hunger and satiety Study day 1, 28, 43 and 70 Fasting plasma will be analyzed for glucagon (pmol/L) as measured by enzyme-linked immunoabsorbant assay
Change in total cholesterol, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for total cholesterol (mmol/L) by Piccolo analyzer
Change in LDL cholesterol, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for LDL cholesterol (mmol/L) by Piccolo analyzer
Change in very low-density lipoprotein (VLDL), a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for very low-density lipoprotein (VLDL) cholesterol (mmol/L) by Piccolo analyzer
Change in alanine aminotransferase, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for alanine aminotransferase (IU/L) by Piccolo analyzer
Change in leptin, a biomarker of hunger and satiety Study day 1, 28, 43 and 70 Fasting plasma will be analyzed for leptin (pmol/L) as measured by enzyme-linked immunoabsorbant assay
Change in ghrelin, a biomarker of hunger and satiety Study day 1, 28, 43 and 70 Fasting plasma will be analyzed for ghrelin (pmol/L) as measured by enzyme-linked immunoabsorbant assay
Change in aspartate aminotransferase, a biomarker of cardiovascular health Study day 1, 28, 43 and 70 Fasting serum will be analyzed for aspartate aminotransferase (IU/L) by Piccolo analyzer
Trial Locations
- Locations (1)
UC Davis, Western Human Nutrition Research Center
🇺🇸Davis, California, United States